Low temperature curable organopolysiloxane coatings

ABSTRACT

A method of making a coated substrate which includes the steps of applying a layer of a coating composition, said coating composition comprising an alkenyl functional organopolysiloxane and a hydride functional organopolysiloxane, to the substrate, said substrate comprising a catalytically effective amount of a precious metal catalyst, and allowing the layer to cure, allows the use of a non-catalyzed coating bath having a very long useful life, while providing a highly reactive coating layer that may be rapidly cured at low temperature.

This application claims rights of priority from U.S. Provisional PatentApplication Serial No. 60/156,082, filed Sep. 24, 1999.

FIELD OF THE INVENTION

The present invention relates to a low temperature curable coatings,more particularly to addition curable organopolysiloxane coatings thatcure rapidly at low temperature.

BRIEF DESCRIPTION OF THE RELATED ART

Addition curable release coating compositions and their use as releasecoatings are known, see, for example, coassigned U.S. Pat. No.4,448,815. A layer of such coating is typically applied to a substrate,such as paper, from a reactive coating bath which contains analkenyl-functional organopolysiloxane, a hydride-functionalorganopolysiloxane, a precious metal catalyst and a cure inhibitor. Onceapplied, the layer of coating is cured by exposing the coated substrateto elevated temperature.

The cure inhibitor retards cure of the coating and enables a balancebetween a long useful coating bath life at low temperature and rapidcure speed at elevated temperature to be maintained. There is a constantdesire in the art to provide increased cure speed without compromisingbath life.

The need to subject the coated substrate to elevated temperature to curethe coating layer introduces some drawbacks to the use of addition cureorganopolysiloxane release coatings coating process, in the form ofenergy costs, a need to rehydrate coated paper substrates after curingand a limited ability to use such coatings to coat temperature sensitivesubstrates, such as, for example, some polymer films. Due to thesedrawbacks, there is a desire in the art to provide coatings that arecurable at lower temperature without compromising bath life.

SUMMARY OF THE INVENTION

In a first aspect, the present invention is directed to a method ofmaking a coated substrate.

In a first embodiment, a method of making a coated substrate comprises:applying a layer of a coating composition, said coating compositioncomprising an alkenyl functional organopolysiloxane and a hydridefunctional organopolysiloxane, to a substrate, said substrate comprisinga catalytically effective amount of a precious metal catalyst, andallowing the layer to cure.

In a second embodiment, a method of making a coated substrate comprises:applying a layer of a first component of a coating composition, saidfirst component comprising an alkenyl functional organopolysiloxane anda catalytically effective amount of a precious metal catalyst to asubstrate, applying a layer a second component of a coating composition,said second component comprising a hydride functionalorganopolysiloxane, to the substrate, and allowing the layers of coatingcomposition to cure.

In a third embodiment, a method of making a coated substrate comprises:applying a layer of a coating composition, said coating compositioncomprising organopolysiloxane having both alkenyl and hydride radicalspresent on the same molecule, to the substrate, said substratecomprising a catalytically effective amount of a precious metalcatalyst, and allowing the layer to cure.

The method of the present invention allows the use of a non-catalyzedcoating bath having a very long useful life, while providing a highlyreactive coating layer that may be rapidly cured at low temperature andthereby avoids some of the drawbacks, for example, high energy costs,the need to rehydrate paper substrates and the limited applicability totemperature sensitive substrates, that characterize typical additioncure coatings.

Another aspect of the present invention is directed to a catalyzedarticle comprising a substrate selected from paper sheets, polymerfilms, polymer coated paper sheets and metal foils, and a precious metalcatalyst disposed on at least one surface of the substrate.

Another aspect of the present invention is directed to a method offorming a catalyzed article, comprising: forming a dilute catalyst bydissolving a precious metal catalyst in a volatile organic ororganosiloxane solvent; or by dispersing a precious metal catalyst in abinder composition; or by dispersing a precious metal catalyst in a filmforming polymer composition, and applying the dilute catalyst to thesubstrate, wherein the composition of the dilute catalyst andapplication rate of dilute catalyst on the substrate are selected toprovide a selected amount of precious metal per unit area of substratesurface.

DETAILED DESCRIPTION OF THE INVENTION

Alkenyl functional organopolysiloxanes suitable for use in the method ofthe present invention are those including structural units of theformula (I):

R¹ _(a)SiO_(4-a/2)  (I)

wherein:

each R¹ is independently hydroxyl or a monovalent hydrocarbon radical,and

a is an integer wherein 0≦a≦3,

provided that at least two R¹ groups per molecule of such alkenylfunctional organopolysiloxane are each independently alkenyl radicals.

As used herein “monovalent hydrocarbon radical” means a monovalentacyclic hydrocarbon radical, a monovalent alicyclic hydrocarbon radicalor a monovalent aromatic hydrocarbon radical.

As used herein, the terminology “acyclic hydrocarbon radical” means amonovalent straight chain or branched hydrocarbon radical, preferablycontaining from 2 to 20 carbon atoms per radical, which may be saturatedor unsaturated and which may be optionally substituted or interruptedwith one or more functional groups, such as, for example, carboxyl,cyano, hydroxy, halo and oxy. Suitable monovalent acyclic hydrocarbonradicals include, for example, alkyl, alkenyl, alkynyl, hydroxyalkyl,cyanoalkyl, carboxyalkyl, carboxamide, alkylamido and haloalkyl, suchas, for example, methyl, ethyl, sec-butyl, tertbutyl, octyl, decyl,dodecyl, cetyl, stearyl, ethenyl, propenyl, butynyl, hydroxypropyl,cyanoethyl, carboxymethyl, chloromethyl and 3,3,3-fluoropropyl.

As used herein the term “alkyl” means a saturated straight or branchedmonovalent hydrocarbon radical. In a preferred embodiment, monovalentalkyl groups are selected from linear or branched alkyl groupscontaining from 1 to 12 carbons per group, such as, for example, methyl,ethyl, propyl, iso-propyl, nbutyl, iso-butyl, sec-butyl, tert-butyl,pentyl, hexyl, heptyl, decyl, dodecyl.

As used herein the term “alkenyl” means a straight or branchedmonovalent terminally unsaturated hydrocarbon radical, preferablycontaining from 2 to 10 carbon atoms per radical, such as, for example,ethenyl, 2-propenyl, 3-butenyl, 5-hexenyl, 7-octenyl and ethenylphenyl.

As used herein, the terminology “monovalent alicyclic hydrocarbonradical” means a monovalent radical containing one or more saturatedhydrocarbon rings, preferably containing from 4 to 10 carbon atoms perring, per radical which may optionally be substituted on one or more ofthe rings with one or more alkyl radicals, each preferably containingfrom 2 to 6 carbon atoms per group, halo radicals or other functionalgroups and which, in the case of a monovalent alicyclic hydrocarbonradical containing two or more rings, may be fused rings. Suitablemonovalent alicyclic hydrocarbon radicals include, for example,cyclohexyl and cyclooctyl.

As used herein, the terminology “monovalent aromatic hydrocarbonradical” means a monovalent hydrocarbon radical containing one or morearomatic rings per radical, which may, optionally, be substituted on thearomatic rings with one or more alkyl radicals, each preferablycontaining from 2 to 6 carbon atoms per group, halo radicals or otherfunctional groups and which, in the case of a monovalent aromatichydrocarbon radical containing two or more rings, may be fused rings.Suitable monovalent aromatic hydrocarbon radicals include, for example,phenyl, tolyl, 2,4,6-trimethylphenyl, 1,2-isopropylmethylphenyl,1-pentalenyl, naphthyl, anthryl.

In a preferred embodiment, the alkenyl functional organopolysiloxanecomprises one or more organopolysiloxane polymers or copolymer of theformula (II):

M¹ _(b)M^(vi) _(c)D¹ _(d)D^(vi) _(e)T¹ _(f)T^(vi) _(g)Q_(h)  (II)

wherein:

M¹ is R² ₃SiO_(1/2),

M^(vi) is R³ ₂R⁴SiO_(1/2),

D¹ is R⁵ ₂SiO_(2/2),

D^(vi) is R⁶R⁷SiO_(2/2),

T¹ is R⁸SiO_(3/2),

T^(vi) is R⁹SiO_(3/2),

Q is SiO_(4/2),

each R², R³, R⁵ ₁ R⁶ and R⁸ is independently hydroxyl or a monovalenthydrocarbon radical,

each R⁴, R⁷ and R⁹ is independently alkenyl,

b, c, d, e, f, g and h are each integers selected to provide polymer ahaving a viscosity of from 50 to 50,000 centiStokes (“cSt”) and having adesired amount of alkenyl groups per molecule, provided at least one ofc, e and g is greater than 0, so that the alkenyl functionalorganopolysiloxane contains at least two alkenyl radicals per molecule.

In a preferred embodiment, R², R³, R⁵, R⁶ and R⁸ are each (C₁-C₆)alkyl,most preferably methyl, R⁴, R⁷ and R⁹ are each independently aterminally unsaturated (C₂-C₆)alkenyl radical, more preferably, ethenylor 5-hexenyl.

In a preferred embodiment, the coefficients b, c, d, e, f, g and h areselected to provide a having a viscosity of from 100 to 1000 cSt, morepreferably from 150 to 500 cSt.

In a more highly preferred embodiment, the alkenyl functionalorganopolysiloxane comprises one or more compounds selected from: linearalkenyl-stopped dialkylsiloxane polymers of the formula M^(vi) ₂D^(d),branched alkenyl-stopped dialkylsiloxane polymers of the formula M¹_(b)M^(vi) _(c)D¹ _(d)T¹ _(f), siloxane polymers of the formula M¹_(b)M^(vi) _(c)Q¹ _(h), alkenyl-stopped alkylalkenyl dialkylpolysiloxanecopolymers of the formula M¹ _(b)M^(vi) _(c)D¹ _(d)D^(vi) _(e), whereinM¹, M^(vi), D¹, D^(vi), T^(f), Q, b, c, d, e and h are each defined asabove, and wherein R², R³, R⁵, R⁶ and R⁸ are each alkyl, preferablymethyl, and wherein R⁴ and R⁷ are each preferably ethenyl.

Hydride functional organopolysiloxanes suitable for use in the method ofthe present invention are those including structural units of thestructural formula (III):

R¹⁰ _(i)SiO_(4-i/2)  (III)

wherein

each R¹⁰ is independently H or a monovalent hydrocarbon radical, and

i is an integer wherein 0≦i≦3,

provided that at least two R¹⁰ groups per molecule of such hydridefunctional organopolysiloxane are each H.

In a preferred embodiment, the hydride functional organopolysiloxane isan organopolysiloxane of the structural formula (IV):

M² _(j)M^(H) _(k)D² _(l)D^(H) _(m)T² _(n)T^(H) _(o)Q_(p)  (IV)

wherein:

M² is R¹¹ ₃SiO_(1/2),

M^(H) is R¹² _(2R) ³SiO_(1/2),

D² is R¹⁴ ₂SiO_(2/2),

D^(H) is R¹⁵R¹⁶SiO_(2/2),

T² is R¹⁷SiO_(3/2),

T^(H) is R¹⁸SiO_(3/2),

Q is SiO_(4/2),

each R¹¹, R¹², R¹⁴, R¹⁵ and R¹⁷ is independently a monovalenthydrocarbon radical,

R¹³, R⁶ and R¹⁸ are each H,

j, k, 1, m, n, o and p are each integers selected to provide a polymerhaving a viscosity of from 1 to 1000 cSt and a desired amount ofsilicon-bonded H radicals per molecule, provided at least one of k, mand o is greater than 0, so that the hydride functionalorganopolysiloxane contains at least two silicon-bonded H radicals permolecule.

In a preferred embodiment, R¹¹, R¹², R¹⁴ and R¹⁵ are each (C₁-C₆)alkyl,most preferably methyl.

In a preferred embodiment, the coefficients b, c, d, e, f, g and h areselected to provide a having a viscosity of from 10 to 150 cSt, morepreferably from 20 to 80 cSt.

In a more highly preferred embodiment, the hydride functionalorganopolysiloxane comprises one or more compounds selected fromtrialkylsiloxy-stopped alkyl hydrogen polysiloxanes of the formula M²_(j)D^(H) _(m), trialkylsiloxy-stopped alkylhydrogen dialkylpolysiloxanecopolymers of the formula M² _(j)D² _(l)D^(H) _(m), wherein M², D²,D^(H), j, l and m are each defined as above, and wherein R¹¹, R⁴ and R¹⁵are each alkyl, preferably methyl.

In an alternative embodiment, the coating composition comprises anorganopolysiloxane having both alkenyl and hydride radicals present onthe same molecule, such as for example the organopolysiloxanes disclosedin coassigned U.S. Pat. Nos. 5,698,654 and 5,753,751, the disclosure ofwhich is hereby incorporated herein by reference.

In a preferred embodiment, the alkenyl and hydride functionalorganopolysiloxane comprises one or more organopolysiloxanes of theformula (V):

M¹ _(q)M^(vi) _(r)M^(H) _(s)D¹ _(s)D^(vi) _(u)D^(H) _(v)T¹ _(w)T^(vi)_(x)T^(H) _(y)Q_(z)  (V)

wherein; M¹, M^(vi), M^(H) D¹, D^(vi), D^(H), T¹, T^(vi), T^(H), Q areeach defined as above and q, r, s, t, u, v, w, x, y and z are eachintegers selected to provide polymer a having a viscosity of from 50 to50,000 cSt and having a desired amount of alkenyl groups andsilicon-bonded H radicals per molecule, provided that each moleculecontains at least two alkenyl groups and at least two silicon-bonded Hradicals.

In a preferred embodiment coating composition exhibits a molar ratio ofsilicon bonded hydrogen on the hydride functional organopolysiloxane toalkenyl groups on the alkenyl functional organopolysiloxane(“Si-H:alkenyl ratio”) of from 1:5 to 5:1, more preferably from 1:1 to4:1 and even more preferably from 1.2:1 to 2.5:1.

The coating composition used in the method of the present invention mayoptionally include other components known in the art, such as, forexample, nonreactive diluents, such as for example, solvents such aswater, hydrocarbon fluids and non-functionalized silicone oils, reactivediluents, such as, for example, vinyl ether compounds, cure inhibitors,cure rate accelerators, fillers, controlled release additives andcolorants.

Substrates suitable for use in the method of the present inventioninclude paper, such as for example, supercalendered kraft paper,glassine paper, machine finished paper and machine glazed paper, andpolymer films, such as, for example, polyolefins, polyesters andpolystyrenics, metal foils, such as for example, aluminum foil andcomposite substrates, such as for example, polyolefin coated kraftpaper.

Precious metal catalysts suitable for use in the method of the presentinvention are those capable of catalyzing the cure of an additioncurable siloxane coating composition. In a preferred embodiment, theprecious metal catalyst comprises one or more of platinum and rhodium.Suitable precious metal. catalysts include, for example, chloroplatinicacid, precious metal salts, such as for example, sodium or potassiumsalts of chloroplatinic acid, platinum halides, organometalliccomplexes, such as, for example, Karstedt's catalyst, platinumcyclohexadiene complex, platinum acetyl acetonate complex, as well asolefinic ligands of platinum or rhodium, and supported precious metalcatalysts, such as platinum deposited on silica or alumina particles,which provide the precious metal in a form that is suitable forcatalyzing the cure of the organopolysiloxane mixture of the coatingcomposition used in the method of the present invention. In a preferredembodiment, the precious metal catalyst comprises a platinum complex ofdivinyl tetramethyl disiloxane.

In a preferred embodiment, a dilute form of the precious metal catalystis made by dissolving the catalyst in a solvent, such as for example,hexane, heptane, octane or a mixture thereof or an organopolysiloxane,or by dispersing the catalyst in a binder composition, for example, abinder composition for finishing paper comprising a polymer latex and aninorganic filler, or by dispersing the catalyst in a film formingpolymer composition, such as, for example, polyvinyl alcohol or apolyacrylate composition, and the dilute form of catalyst is applied tothe substrate, by for example, spray coating, roll coating, rod coatingor extrusion, to form a precious metal catalyst-containing substrate.

Alternatively, the catalyst is dissolved in an alkenyl functionalorganopolysiloxane and a layer of the an alkenyl functionalorganopolysiloxane/catalyst solution is applied to the substrate.

As used herein, “catalytically effective amount” means an amounteffective to catalyze the cure of a layer of coating disposed on thesubstrate. In a preferred embodiment, the precious metalcatalyst-containing substrate contains greater than about 0.000001 g,more preferably from 0.00005 to 0.01 g, and still more preferably, from0.0005 to 0.001 g, of precious metal per square meter of substratesurface.

A layer of the coating composition is applied to the substrate by forexample, spray coating, roll coating, rod coating or extrusion andallowed to cure. The layer of coating composition may be allowed to cureat uncontrolled ambient temperature or may be allowed to cure at anelevated temperature, such as for example, a temperature of up to about100° C., more preferably up to about 70° C., and still more preferably,up to about 40° C.

The coated substrate made by the method of the present invention isuseful a release liner for pressure sensitive adhesive-backed articlessuch as, for example, adhesive labels and adhesives tapes.

An adhesive laminate comprises a coated substrate made by the method ofthe present invention laminated with a pressure sensitive adhesivecoated substrate, such that the cured coating layer of the coatedsubstrate made by the method of the present invention is in contact withthe pressure sensitive adhesive layer on the pressure sensitive adhesivecoated substrate. Suitable pressure sensitive adhesive compositions,such as, for example, emulsion acrylic adhesives, solvent acrylicadhesives, hot melt adhesives, emulsion rubber adhesive, solvent rubberadhesives, and methods for making pressure sensitive adhesive coatedsubstrates are well known in the art. The pressure sensitive adhesivecoated substrate may be easily removed from the coated substrate made bythe method of the present invention and applied to another substrate, asdesired.

EXAMPLE 1

A paper substrate (super-calendered kraft paper) was coated with axylene. solution of Karstedt's catalyst by applying approximated 1milliliter of a 5% platinum by weight solution to a 6 inch by 3 inchpaper sheet and then allowing the xylene to evaporate. A layer of acoating composition containing 5 grams of a vinyl stoppeddimethylsiloxane polymer (structural formula M_(vi) ₂D¹ _(d), whereinM^(vi), D¹ and d are each as described above, and R³ and R⁵ are eachmethyl, R⁴ is ethenyl, and exhibiting a viscosity of about 250 cSt) and0.5 grams of a trimethylsiloxy-stopped methylhydrogen dimethylsiloxanepolymer (formula M² ₂D² ₁D^(H) _(m), wherein M², D², D^(H), l and m areeach as described above, R¹¹, R¹⁴ and R¹⁵ are each methyl and R¹⁶ is H,containing approximately 1 wt % hydride radicals and exhibiting aviscosity of about 35 cSt) was applied to the platinum-containing papersubstrate in a bead and drawn down across the paper with a straightmetal edge. Cure was qualitatively assessed by rubbing the layer with afingertip immediately after application of the coating layer to thesubstrate. The coating did not smear, indicating that the coating hadcured very rapidly at room temperature.

EXAMPLE 2

A hexenyl-stopped polydimethyl siloxane polymer (structural formulaM^(vi) ₂D¹ _(d), wherein M^(vi), D¹ and d are each as described above,R³ and R⁵ are each methyl, and R⁴ is hexenyl, and exhibiting a viscosityof about 250 cSt) was mixed with Karstedt's catalyst to make a mixturecontaining 270 parts per million platinum. The platinum-catalyzedpolysiloxane mixture was applied to a paper substrate (super-calenderedkraft paper) by the same technique as described above in Example 1. Thecoated paper was then coated with a layer of the trimethylsiloxy-stoppedmethylhydrogen dimethylsiloxane polymer described above in Example 1.The coating was found to have cured within 15 seconds of the applicationof the trimethylsiloxy-stopped methylhydrogen dimethylsiloxane polymer.

EXAMPLE 3

A solution of a platinum divinyl tetramethyl siloxane complex in hexane(0.5% Pt) was coated on Kammerer AV100 glassine paper using a #3 Meyerrod and the solvent was then flashed off for 10 seconds at 160° F. in aforced air oven to form a Pt coated paper substrate. A mixture of 50parts by weight (“pbw”) of a vinyl-stopped dimethylsiloxane polymer(formula M^(vi) ₂D¹ _(d), wherein M^(vi), D¹ and d are each as describedabove, and R³ and R⁵ are each methyl, R⁴ is ethenyl, and exhibiting aviscosity of about 225 cSt) and 2.5 pbw of the trimethylsilyl-stoppedmethylhydrogen dimethyl polysiloxane copolymer used in Example 1 werecoated on top of the Pt-coated paper using a doctor blade. The liquidcoating was found to cure almost immediately on contact with thePt-coated paper substrate.

The extent of cure was qualitatively assessed by a tape migration testand rubbing the surface of the cured siloxane coating layer with afingertip. The tape migration test was conducted by firmly pressing theadhesive side of a piece of 3M Scotch® 610 tape to the surface of thecured siloxane coating, peeling the tape off and then making a loop ofthe tape such that the adhesive side of the tape was brought intocontact with itself. Migration of uncured siloxane coating to theadhesive side of the tape would interfere with the ability of the tapeto stick to itself. The surface of the cured coating layer was thenrubbed vigorously with a fingertip and then the surface was visuallyexamined. Smearing of the coating layer was taken as being indicative ofan incompletely cured coating layer. The relative difficulty of markingthe coating, that is, making visually detectable deformations of thecoating surface, by fingertip rubbing was taken as being indicative ofthe hardness of the cured coating layer, with increasing difficulty inmarking being indicative of greater hardness.

The tape migration test for the coating of Example 3 showed that thetape stuck to itself well, indicating that it had not been contaminatedwith a significant amount of silicone. The coating of Example 3 did notsmear, but could be marked fairly easily when the surface of the coatingwas rubbed with a fingertip.

EXAMPLE 4

The procedure of Example 3 was repeated, except that the silicone coatedpaper, was place in a forced air oven at 160° F. for 5 secondsimmediately after coating the paper with the silicone mixture.

The tape migration test for the coating of Example 4 showed that thetape stuck to itself well, indicating that it had not been contaminatedwith a significant amount of silicone. The coating of Example 4 did notsmear, but could be marked somewhat when the surface of the coating wasrubbed with a fingertip.

EXAMPLE 5

The procedure of Example 3 was repeated, except that Thilmanypolyethylene kraft (PEK) substrate was substituted for the KammererAV100 glassine paper.

The tape migration test for the coating of Example 5 showed that thetape stuck to itself well, indicating that it had not been contaminatedwith a significant amount of silicone. The coating of Example 5 did notsmear and exhibited no marking when the surface of the coating wasrubbed with a fingertip.

EXAMPLE 6

The procedure of Example 5 was repeated, except that the siliconeformulation used was a mixture of 50 pbw of a branched alkenylfunctional polymer (approximate structure M^(Vi) _(3.75)M¹ _(0.5)T¹_(4.5)D¹ ₁₀₀, wherein M¹, M^(vi), T¹ and D¹ are each defined as above,with R², R³, R⁵ and R⁸ each being methyl and R⁴ being ethenyl, andexhibiting a viscosity of 208 cSt) and 3.0 pbw of the methyl hydrogendimethyl polysiloxane copolymer used in Example 3.

The tape migration test for the coating of Example 6 showed that thesome migration to the tape immediately after coating, as evidenced bythe fact that the tape did not stick well to itself after being incontact with the siloxane coating layer. The coating of Example 6smeared when rubbed with a fingertip. A recheck after about a minuteshowed no migration to the tape and no smearing of the coating.

EXAMPLE 7

The procedure of Example 3 was repeated, except that a 2 mil polyesterfilm was substituted for was substituted for the Kammerer AV100 glassinepaper used in Example 3.

The tape migration test for the coating of Example 7 showed that thetape stuck to itself well, indicating that it had not been contaminatedwith a significant amount of silicone. The coating of Example 7 did notsmear and exhibited some marking when the surface of the coating wasrubbed with a fingertip.

EXAMPLE 8

The silicone coating composition of Example 6 was coated on a Pt-treated2 mil polyester film and then heated at 160° F. for 10 seconds.

The tape migration test for the coating of Example 8 showed that thetape stuck to itself well, indicating that it had not been contaminatedwith a significant amount of silicone. The coating of Example 8 did notsmear and exhibited some marking when the surface of the coating wasrubbed with a fingertip.

The method of the present invention allows the use of a non-catalyzedcoating bath having a very long useful life, while providing a highlyreactive coating layer that may be rapidly cured at low temperature andthereby avoids some of the drawbacks, for example, high energy costs,the need to rehydrate paper substrates and the limited applicability totemperature sensitive substrates, that characterize typical additioncure coatings.

What is claimed is:
 1. A method of making a coated substrate, comprisingapplying a coating composition, said coating composition comprising analkenyl functional compound and a hydride functional compound, to asubstrate, said substrate comprising a catalytically effective amount ofa precious metal catalyst, and allowing the coating composition to cure.2. The method of claim 1, wherein the alkenyl functional compoundcomprises an organopolysiloxane comprising structural units of theformula: R¹ _(a)SiO_(4-a/2) wherein each R¹ is independently hydroxyl ora monovalent hydrocarbon radical, and a is an integer wherein 0≦a≦3 andprovided that at least two R¹ groups per molecule of such alkenylfunctional organopolysiloxane are each independently alkenyl radicals.3. The method of claim 1, wherein the alkenyl functional compoundcomprises one or more organopolysiloxane polymers or copolymers of theformula: M¹ _(b)M^(vi) _(c)D¹ _(d)D^(vi) _(e)T¹ _(f)T^(vi) _(g)Q_(h)wherein: M¹ is R² ₃SiO_(1/2), M^(vi) is R³ ₂R⁴SiO_(1/2), D¹ is R⁵₂SiO_(2/2), D^(vi) is R⁶R⁷SiO_(2/2,) T¹ is R⁸SiO_(3/2), T^(vi) isR⁹SiO_(3/2), Q is SiO_(4/2), each R², R³, R⁵, R⁶ and R⁸ is independentlyhydroxyl or a monovalent hydrocarbon radical, each R⁴, R⁷ and R⁹ isindependently alkenyl, b, c, d, e, f, g and h are each integers selectedto provide polymer a having a viscosity of from 50 to 50,000centiStokes, provided at least one of c, e and g is greater than 0 andthe alkenyl functional organopolysiloxane contains at least two alkenylradicals per molecule.
 4. The method of claim 1, wherein the hydridefunctional compound comprises an organopolysiloxane comprisingstructural units of the structural formula: R¹⁰ _(i)SiO_(4-i/2) whereineach R¹⁰ is independently H or a monovalent hydrocarbon radical, and iis an integer wherein 0≦i≦3, provided that at least two R¹⁰ groups permolecule of such hydride functional organopolysiloxane are each H. 5.The method of claim 1, wherein the hydride functional compound comprisesone or more organopolysiloxanes of the structural formula: M² _(j)M^(H)_(k)D² _(l)D^(H) _(m)T² _(n)T^(H) _(o)Q_(p) wherein: M² is R¹¹₃SiO_(1/2), M^(H) is R¹² ₂R¹³SiO_(1/2), D² is R¹⁴ ₂SiO_(2/2), D^(H) isR¹⁵R¹⁶SiO_(2/2), T² is R¹⁷SiO_(3/2), T^(H) is R¹⁸SiO_(3/2), Q isSiO_(4/2), each R¹¹, R¹², R¹⁴, R¹⁵ and R¹⁷ is independently a monovalenthydrocarbon radical, R¹³, R¹⁶ and R¹⁸ are each H, j, k, l, m, n, o and pare each integers selected to provide a polymer having a viscosity offrom 1 to 1000 centiStokes, provided at least one of k, m and o isgreater than 0 and the hydride functional organopolysiloxane contains atleast two silicon-bonded H radicals per molecule.
 6. The method of claim1, wherein the substrate comprises paper, a polymer film, a metal foilor a combination thereof.
 7. The method of claim 1, wherein the preciousmetal catalyst comprises one or more of platinum and rhodium.
 8. Themethod of claim 1, wherein the catalytically effective amount ofprecious metal catalyst is an amount greater than about 0.000001 gram ofprecious metal per square meter of substrate surface.
 9. The method ofclaim 1, wherein the catalytically effective amount of precious metalcatalyst is an amount of from 0.00005 gram to 0.01 gram of preciousmetal per square meter of substrate surface.
 10. The method of claim 1,wherein the catalytically effective amount of precious metal catalyst isan amount of from 0.0005 gram to 0.001 gram of precious metal per squaremeter of substrate surface.
 11. The method of claim 1, wherein a layerof the coating composition is applied to the substrate by spray coating,roll coating, rod coating or extrusion.
 12. The method of claim 1,wherein the layer of coating composition is allowed to cure atuncontrolled ambient temperature or at an elevated temperature.
 13. Themethod of claim 12, wherein the layer of coating composition is allowedto cure at uncontrolled ambient temperature.
 14. The method of claim 12,comprising allowing the layer of coating composition to cure at anelevated temperature of up to about 100° C.
 15. A coated substrate madeby the method of claim 1.